The Dunning R3327 transplantable prostatic adenocarcinoma in the Fischer-Copenhagen F1 hybrid rat is the experimental model to study host immunological response to the tumor and to characterize tumor antigen sublines of the tumor with different degrees of differentiation will be used in the studies. Immunological parameters including lymphocyte blastogeneses, cytotoxicity and cell markers will be determined throughout the progression of the disease. Surface glycoproteins of the tumors will be isolated, purified and characterized biochemically and immunochemically. The relationship of these purified membrane glycoproteins to tumor antigens will be ascertained.